JP2015224657A - Load sensing control circuit - Google Patents

Load sensing control circuit Download PDF

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Publication number
JP2015224657A
JP2015224657A JP2014108124A JP2014108124A JP2015224657A JP 2015224657 A JP2015224657 A JP 2015224657A JP 2014108124 A JP2014108124 A JP 2014108124A JP 2014108124 A JP2014108124 A JP 2014108124A JP 2015224657 A JP2015224657 A JP 2015224657A
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pressure
valve
compensator
actuator
valves
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JP6292979B2 (en
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剛 寺尾
Takeshi Terao
剛 寺尾
中村　雅之
Masayuki Nakamura
雅之 中村
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KYB Corp
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KYB Corp
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Priority to JP2014108124A priority Critical patent/JP6292979B2/en
Priority to CN201580001310.8A priority patent/CN105392999B/en
Priority to US14/898,161 priority patent/US10024342B2/en
Priority to KR1020157035201A priority patent/KR101718278B1/en
Priority to DE112015000092.5T priority patent/DE112015000092T5/en
Priority to PCT/JP2015/061398 priority patent/WO2015182268A1/en
Publication of JP2015224657A publication Critical patent/JP2015224657A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
    • F15B11/163—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for sharing the pump output equally amongst users or groups of users, e.g. using anti-saturation, pressure compensation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
    • F15B11/162—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for giving priority to particular servomotors or users
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/026—Pressure compensating valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/06—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with two or more servomotors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/005—Filling or draining of fluid systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20546—Type of pump variable capacity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/25—Pressure control functions
    • F15B2211/253—Pressure margin control, e.g. pump pressure in relation to load pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • F15B2211/3053—In combination with a pressure compensating valve
    • F15B2211/3054—In combination with a pressure compensating valve the pressure compensating valve is arranged between directional control valve and output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/35—Directional control combined with flow control
    • F15B2211/351—Flow control by regulating means in feed line, i.e. meter-in control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40553—Flow control characterised by the type of flow control means or valve with pressure compensating valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50563—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure
    • F15B2211/50572—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure using a pressure compensating valve for controlling the pressure difference across a flow control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/575—Pilot pressure control
    • F15B2211/5756—Pilot pressure control for opening a valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/78—Control of multiple output members
    • F15B2211/781—Control of multiple output members one or more output members having priority

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

PROBLEM TO BE SOLVED: To change a flow dividing ratio determined on the basis of a switching amount of a switch valve, according to a purpose.SOLUTION: Load pressures of actuators A1, A2 to which compensator valves C1, C2 are connected, are guided to pressure chambers 9, 10 of one of the compensator valves C1, C2, a maximum load pressure selected by selecting means 4, is guided to pressure chambers 11, 12 of the other one of the compensator valves C1, C2, and openings of the compensator valves C1, C2 are controlled by pressure actions of both pressure chambers 9, 10 and 11, 12, thus a pump discharge amount is divided according to a switching amount of a plurality of switch valves V1, V2. A drain passage 13 is disposed to connect the pressure chambers 9, 10 of one of the compensator valves C1, C2 to a tank T, and a flow dividing ratio changing valve CV for controlling the pressures of the pressure chambers 9, 10 at one side is disposed in the drain passage 13.

Description

この発明は、複数のアクチュエータの負荷圧変動にかかわりなく、各切換弁の開度に応じて分流するロードセンシング制御回路に関する。   The present invention relates to a load sensing control circuit that diverts according to the opening degree of each switching valve regardless of load pressure fluctuations of a plurality of actuators.

この種のロードセンシング制御回路として、特許文献１に記載されたものが従来から知られているが、この特許文献１における回路図を示したのが図２である。   As this type of load sensing control circuit, the one described in Patent Document 1 has been conventionally known, and FIG. 2 shows a circuit diagram in Patent Document 1.

可変容量型ポンプ１には切換弁Ｖ１，Ｖ２を接続している。この切換弁Ｖ１，Ｖ２には、図示しないスプールが摺動自在に組み込まれている。なお、切換弁Ｖ１，Ｖ２は、上記スプールのストロークに応じてその開度を可変にするものなので、図２においては、切換弁Ｖ１，Ｖ２を可変オリフィスの記号で示している。   The variable displacement pump 1 is connected to switching valves V1 and V2. A spool (not shown) is slidably incorporated in the switching valves V1 and V2. Since the switching valves V1 and V2 are variable in opening according to the stroke of the spool, the switching valves V1 and V2 are indicated by a variable orifice symbol in FIG.

上記切換弁Ｖ１，Ｖ２の下流には、コンペンセータバルブＣ１，Ｃ２を接続するとともに、このコンペンセータバルブＣ１，Ｃ２の下流にアクチュエータＡ１，Ａ２を接続している。つまり、コンペンセータバルブＣ１，Ｃ２は、切換弁Ｖ１，Ｖ２及びアクチュエータＡ１，Ａ２とを接続する接続過程に設けられている。そして、これら両アクチュエータＡ１，Ａ２のヘッド側室２，３のそれぞれは最高負荷圧を選択する選択手段４に接続され、この選択手段４によって、上記ヘッド側室２，３のうちのどちらか高いほうの負荷圧Ｐ２が選択される。   Compensator valves C1 and C2 are connected downstream of the switching valves V1 and V2, and actuators A1 and A2 are connected downstream of the compensator valves C1 and C2. That is, the compensator valves C1 and C2 are provided in a connection process for connecting the switching valves V1 and V2 and the actuators A1 and A2. Each of the head side chambers 2 and 3 of these actuators A1 and A2 is connected to a selection means 4 for selecting the maximum load pressure. By this selection means 4, the higher one of the head side chambers 2 and 3 is selected. The load pressure P2 is selected.

上記選択手段４で選択された最高負荷圧Ｐ２は、上記可変容量型ポンプ１に設けたレギュレータ５に導かれ、その最高負荷圧Ｐ２に応じて、可変容量型ポンプ１の傾転角が制御され、当該可変容量型ポンプ１が上記最高負荷圧Ｐ２に対応した吐出圧Ｐ１と吐出量を保つようにしている。
なお、図中符号Ｔはタンク、６はレギュレータ５とタンクＴとの間の圧力を保つためのオリフィスである。 The maximum load pressure P2 selected by the selection means 4 is guided to the regulator 5 provided in the variable displacement pump 1, and the tilt angle of the variable displacement pump 1 is controlled according to the maximum load pressure P2. The variable displacement pump 1 maintains the discharge pressure P1 and the discharge amount corresponding to the maximum load pressure P2.
In the figure, reference numeral T denotes a tank, and 6 denotes an orifice for maintaining the pressure between the regulator 5 and the tank T.

コンペンセータバルブＣ１，Ｃ２は、一方の圧力室９，１０と他方の圧力室１１，１２とを設け、これら一方の圧力室９，１０と他方の圧力室１１，１２との圧力作用で開度が制御される。
さらに詳しくは、コンペンセータバルブＣ１，Ｃ２には、図示しないスプール（以下「コンペスプール」という）を摺動自在に設けるとともに、このコンペスプールの一端を上記一方の圧力室９，１０に臨ませ、他端を上記他方の圧力室１１，１２に臨ませている。そして、このコンペスプールは、一方の圧力室９，１０と他方の圧力室１１，１２との圧力作用で、移動位置が制御されるとともに、その移動位置に応じて、切換弁Ｖ１，Ｖ２からアクチュエータＡ１，Ａ２にいたる過程の開度が制御される。 The compensator valves C1 and C2 are provided with one pressure chambers 9 and 10 and the other pressure chambers 11 and 12, and the opening degree is increased by the pressure action between the one pressure chambers 9 and 10 and the other pressure chambers 11 and 12. Be controlled.
More specifically, the compensator valves C1 and C2 are each provided with a spool (not shown) (hereinafter referred to as “compet spool”) that is slidable. The end faces the other pressure chamber 11, 12. The competition spool is controlled by the pressure action between the one pressure chamber 9 and 10 and the other pressure chamber 11 and 12, and the actuator is operated from the switching valves V1 and V2 according to the movement position. The opening degree in the process from A1 to A2 is controlled.

さらに、上記一方の圧力室９，１０には、当該コンペンセータバルブＣ１，Ｃ２と切換弁Ｖ１，Ｖ２との間の圧力Ｐ３，Ｐ４が導かれ、他方の圧力室１１，１２には、選択手段４で選択された最高負荷圧Ｐ２が導かれる。ただし、上記圧力Ｐ３，Ｐ４は、切換弁Ｖ１，Ｖ２の開度に応じた圧力損失分だけ、可変容量型ポンプ１の吐出圧Ｐ１よりも低くなるのは当然である。   Further, pressures P3 and P4 between the compensator valves C1 and C2 and the switching valves V1 and V2 are guided to the one pressure chambers 9 and 10, and selection means 4 is provided to the other pressure chambers 11 and 12. The maximum load pressure P2 selected in (1) is derived. However, the pressures P3 and P4 are naturally lower than the discharge pressure P1 of the variable displacement pump 1 by a pressure loss corresponding to the opening degree of the switching valves V1 and V2.

また、上記圧力Ｐ３，Ｐ４は、アクチュエータＡ１，Ａ２の負荷圧に比例して変化する。例えば、アクチュエータＡ１，Ａ２の負荷圧が高くなれば、それにともなって圧力Ｐ３，Ｐ４も高くなるし、負荷圧が低くなれば圧力Ｐ３，Ｐ４も低くなる。
したがって、コンペンセータバルブＣ１，Ｃ２の一方の圧力室９，１０には、アクチュエータＡ１，Ａ２の負荷圧に応じて変化する圧力Ｐ３，Ｐ４が導かれることになる。 The pressures P3 and P4 change in proportion to the load pressures of the actuators A1 and A2. For example, when the load pressure of the actuators A1 and A2 is increased, the pressures P3 and P4 are increased accordingly, and when the load pressure is decreased, the pressures P3 and P4 are also decreased.
Therefore, pressures P3 and P4 that change according to the load pressure of the actuators A1 and A2 are introduced into one of the pressure chambers 9 and 10 of the compensator valves C1 and C2.

そして、コンペンセータバルブＣ１，Ｃ２は、上記最高負荷圧Ｐ２と上記圧力Ｐ３，Ｐ４とがバランスする位置を保持するとともに、そのバランス位置において当該コンペンセータバルブＣ１，Ｃ２の開度を維持する。
例えば、他方の圧力室１１，１２に導かれる最高負荷圧Ｐ２に対して、反対側の一方の圧力室９，１０に導かれる圧力Ｐ３，Ｐ４の圧力が低ければ低いほどコンペンセータバルブＣ１，Ｃ２の開度が小さくなり、最高負荷圧Ｐ２と圧力Ｐ３，Ｐ４との相対差が小さくなればなるほど、コンペンセータバルブＣ１，Ｃ２の開度は大きくなる。 The compensator valves C1 and C2 maintain a position where the maximum load pressure P2 and the pressures P3 and P4 balance, and maintain the opening of the compensator valves C1 and C2 at the balance position.
For example, with respect to the maximum load pressure P2 guided to the other pressure chambers 11 and 12, the lower the pressures P3 and P4 guided to the one pressure chambers 9 and 10 on the opposite side, the lower the compensator valves C1 and C2. The smaller the opening and the smaller the relative difference between the maximum load pressure P2 and the pressures P3 and P4, the larger the opening of the compensator valves C1 and C2.

一方、両切換弁Ｖ１，Ｖ２が中立位置から切り換えられると、当該切換弁Ｖ１，Ｖ２は、その切り換え量に応じた開度を維持するが、これら両切換弁Ｖ１，Ｖ２の開度の比が、各アクチュエータＡ１，Ａ２に対する可変容量型ポンプ１の吐出量の分流比になる。   On the other hand, when the switching valves V1, V2 are switched from the neutral position, the switching valves V1, V2 maintain the opening according to the switching amount, but the ratio of the opening of the switching valves V1, V2 is Thus, the discharge ratio of the variable displacement pump 1 with respect to the actuators A1 and A2 is a diversion ratio.

しかし、切換弁Ｖ１，Ｖ２の開度で定めた分流比が一定だとしても、アクチュエータＡ１，Ａ２の負荷圧が変化してしまえば、切換弁Ｖ１，Ｖ２の開度によって定めた上記分流比が保たれなくなる。例えば、アクチュエータＡ１，Ａ２の負荷圧が変化して、一方のアクチュエータの負荷圧が、他方のアクチュエータの負荷圧よりも低くなったとする。このときには、たとえ切換弁Ｖ１，Ｖ２の開度に変化がなくても、可変容量型ポンプ１の吐出流体は、負荷の軽い一方のアクチュエータの方に多く流れてしまい、切換弁Ｖ１，Ｖ２の開度で定めた分流比を保つことができなくなる。   However, even if the diversion ratio determined by the opening degree of the switching valves V1, V2 is constant, if the load pressure of the actuators A1, A2 changes, the diversion ratio determined by the opening degree of the switching valves V1, V2 will be It will not be kept. For example, it is assumed that the load pressures of the actuators A1 and A2 change, and the load pressure of one actuator becomes lower than the load pressure of the other actuator. At this time, even if there is no change in the opening degree of the switching valves V1, V2, the discharge fluid of the variable displacement pump 1 flows more to one of the lighter actuators, and the switching valves V1, V2 are opened. The diversion ratio determined in degrees cannot be maintained.

コンペンセータバルブＣ１，Ｃ２は、アクチュエータＡ１，Ａ２の負荷圧が変化した場合にも、切換弁Ｖ１，Ｖ２の開度で定めた分流比を一定に保つ機能を果たすが、次に、その原理を説明する。
ただし、以下の説明において、一方のアクチュエータＡ１が最高負荷圧Ｐ２を維持し、他方のアクチュエータＡ２の負荷圧が上記最高負荷圧Ｐ２よりも低い場合であって、一度設定された切換弁Ｖ１，Ｖ２の開度は変化しないことを前提にする。 The compensator valves C1 and C2 function to keep the diversion ratio determined by the opening degree of the switching valves V1 and V2 even when the load pressure of the actuators A1 and A2 changes. Next, the principle will be described. To do.
However, in the following description, when one actuator A1 maintains the maximum load pressure P2 and the load pressure of the other actuator A2 is lower than the maximum load pressure P2, the switching valves V1 and V2 set once. It is assumed that the opening degree of the valve does not change.

上記の場合に、可変容量型ポンプ１の吐出圧Ｐ１が最も高いのは当然である。そして、圧力Ｐ３は、コンペンセータバルブＣ１を流れる流体の圧力損失分だけ、アクチュエータＡ１の負荷圧すなわち最高負荷圧Ｐ２よりも高い圧力を維持する。したがって、各圧力は、Ｐ１＞Ｐ３＞Ｐ２の関係を保つ。   In the above case, it is natural that the discharge pressure P1 of the variable displacement pump 1 is the highest. The pressure P3 is maintained at a pressure higher than the load pressure of the actuator A1, that is, the maximum load pressure P2 by the pressure loss of the fluid flowing through the compensator valve C1. Therefore, each pressure maintains the relationship of P1> P3> P2.

上記の関係を維持している中で、一方のコンペンセータバルブＣ１のコンペスプールは、一方の圧力室９における圧力Ｐ３の作用力と他方の圧力室１１における最高負荷圧Ｐ２の作用力とがバランスする位置を保つとともに、コンペンセータバルブＣ１は、コンペスプールの上記位置における開度を維持する。   While maintaining the above relationship, the competing spool of one compensator valve C1 balances the acting force of the pressure P3 in one pressure chamber 9 and the acting force of the maximum load pressure P2 in the other pressure chamber 11. While maintaining the position, the compensator valve C1 maintains the opening of the competition spool at the above position.

そして、アクチュエータＡ１の負荷圧すなわち最高負荷圧Ｐ２が変化すれば、それに応じてコンペンセータバルブＣ１の開度も変化するとともに、その変化に応じて上記圧力Ｐ３も変化する。つまり、コンペンセータバルブＣ１の開度が大きくなれば、その分、このコンペンセータバルブＣ１を通過する流体の圧力損失が小さくなる。また、コンペンセータバルブＣ１の開度が小さくなれば、逆に、上記圧力損失が大きくなる。   When the load pressure of the actuator A1, that is, the maximum load pressure P2 changes, the opening of the compensator valve C1 changes accordingly, and the pressure P3 also changes according to the change. That is, if the opening degree of the compensator valve C1 increases, the pressure loss of the fluid passing through the compensator valve C1 decreases accordingly. On the contrary, if the opening of the compensator valve C1 is reduced, the pressure loss is increased.

また、アクチュエータＡ２側における圧力Ｐ４は、上記他方のコンペンセータバルブＣ２を通過する流体の圧力損失分だけ、当該アクチュエータＡ２の負荷圧よりも高い圧力を維持している。ただし、その圧力Ｐ４と上記最高負荷圧Ｐ２との相対差は上記アクチュエータＡ２の負荷圧に応じて異なることになる。
そして、他方のコンペンセータバルブＣ２は、一方の圧力室１０における圧力Ｐ４の作用力と他方の圧力室１２における最高負荷圧Ｐ２の作用力とがバランスする位置を保つとともに、コンペンセータバルブＣ２は、コンペスプールの上記位置における開度を維持する。 Further, the pressure P4 on the actuator A2 side maintains a pressure higher than the load pressure of the actuator A2 by the amount of pressure loss of the fluid passing through the other compensator valve C2. However, the relative difference between the pressure P4 and the maximum load pressure P2 varies depending on the load pressure of the actuator A2.
The other compensator valve C2 maintains a position where the acting force of the pressure P4 in one pressure chamber 10 and the acting force of the maximum load pressure P2 in the other pressure chamber 12 are balanced, and the compensator valve C2 The opening at the above position is maintained.

アクチュエータＡ２の負荷圧の変化に応じて圧力Ｐ４が変化すれば、それに応じてコンペンセータバルブＣ２の開度も変化する。コンペンセータバルブＣ２の開度が大きくなれば、その分、圧力損失が小さくなる。また、コンペンセータバルブＣ２の開度が小さくなれば、逆に圧力損失が大きくなる。   If the pressure P4 changes according to the change in the load pressure of the actuator A2, the opening degree of the compensator valve C2 also changes accordingly. As the opening of the compensator valve C2 increases, the pressure loss decreases accordingly. Moreover, if the opening degree of the compensator valve C2 is reduced, the pressure loss is increased.

今、一方のアクチュエータＡ１の最高負荷圧が一定で、他方のアクチュエータＡ２の負荷圧が、低くなる方向に変化したとすれば、それにともなって圧力Ｐ４も低くなる。しかし、このときには、コンペンセータバルブＣ２の開度が小さくなるので、そこを通過する流体の圧力損失が大きくなる。このように圧力損失が大きくなれば、アクチュエータＡ２の負荷圧が低くなったとしても、圧力Ｐ４は一定に保たれる。   Now, if the maximum load pressure of one actuator A1 is constant and the load pressure of the other actuator A2 changes in a decreasing direction, the pressure P4 also decreases accordingly. However, at this time, since the opening degree of the compensator valve C2 becomes small, the pressure loss of the fluid passing therethrough becomes large. If the pressure loss increases as described above, the pressure P4 is kept constant even if the load pressure of the actuator A2 is reduced.

したがって、アクチュエータＡ２の負荷圧の変化にかかわりなく、コンペンセータバルブＣ２の上流側の圧力Ｐ４が一定に保たれることになる。このようにアクチュエータＡ２の負荷圧の変化にかかわりなく圧力Ｐ４が一定に保たれるので、切換弁Ｖ２前後の差圧も一定に保たれる。切換弁Ｖ２前後の差圧が一定に保たれれば、アクチュエータＡ２の負荷圧の変化にかかわりなく、切換弁Ｖ２を通過する流量も一定に保たれる。言い換えると、切換弁Ｖ１，Ｖ２の開度で定められた分流比は、負荷圧の変化にかかわりなく一定に保たれることになる。   Accordingly, the pressure P4 on the upstream side of the compensator valve C2 is kept constant regardless of the change in the load pressure of the actuator A2. Thus, since the pressure P4 is kept constant regardless of the change in the load pressure of the actuator A2, the pressure difference across the switching valve V2 is also kept constant. If the differential pressure across the switching valve V2 is kept constant, the flow rate passing through the switching valve V2 is kept constant regardless of the change in the load pressure of the actuator A2. In other words, the diversion ratio determined by the opening degree of the switching valves V1 and V2 is kept constant regardless of the change in load pressure.

特開２００４−２３９３７８号公報JP 2004-239378 A

複数のアクチュエータの負荷圧変動にかかわりなく、各切換弁の開度に応じた分流比を一定に保つロードセンシング制御回路において、切換弁の切り換え量に応じて分流比があらかじめ設定されていたとしても、場合によっては、特定のアクチュエータに対する分流比だけを変更したいという要望がある。   Even in the load sensing control circuit that keeps the diversion ratio according to the opening degree of each switching valve constant regardless of the load pressure fluctuation of multiple actuators, even if the diversion ratio is preset according to the switching amount of the switching valve In some cases, there is a desire to change only the diversion ratio for a specific actuator.

例えば、パワーショベルの場合であれば、ブームシリンダだけを通常のものよりも大きくして、大きな負荷に対応させる場合がある。この場合には、ブームシリンダの負荷圧が非常に高くなるが、この高くなった負荷圧を、可変容量型ポンプのレギュレータに導くと、当該可変容量型ポンプの吐出量が必要以上に少なくなってしまう。   For example, in the case of a power shovel, only the boom cylinder may be made larger than a normal one to cope with a large load. In this case, the load pressure of the boom cylinder becomes very high. However, if this increased load pressure is led to the regulator of the variable displacement pump, the discharge amount of the variable displacement pump becomes smaller than necessary. End up.

可変容量型ポンプの吐出量が必要以上に少なくなった状態を放置しておけば、ブームシリンダに対する供給流量も少なくなり、当該ブームシリンダの作動速度が遅くなってしまう。したがって、このような場合には、ブームシリンダの分流比を、他のアクチュエータの分流比よりも大きくすることが望まれる。   If the state in which the discharge amount of the variable displacement pump is reduced more than necessary is left unattended, the supply flow rate to the boom cylinder also decreases, and the operating speed of the boom cylinder becomes slow. Therefore, in such a case, it is desirable to make the shunt ratio of the boom cylinder larger than the shunt ratio of other actuators.

また、アクチュエータは全て従来と同じであっても、作業の種類によっては、特定のアクチュエータに対する分流比を大きくしたいという要望もあった。
しかしながら、上記のようにした従来のロードセンシング制御回路では、切換弁の切り換え量が決まれば、それに応じた分流比は常に一定であり、上記のような分流比の変更という要望には応えられなかった。 In addition, even though all actuators are the same as conventional ones, there has been a demand to increase the diversion ratio for a specific actuator depending on the type of work.
However, in the conventional load sensing control circuit as described above, if the switching amount of the switching valve is determined, the diversion ratio corresponding to the change amount is always constant, and it cannot meet the request for the change of the diversion ratio as described above. It was.

この発明の目的は、切換弁の切り換え量で決まる分流比を変更できるロードセンシング制御回路を提供することである。   An object of the present invention is to provide a load sensing control circuit capable of changing a diversion ratio determined by a switching amount of a switching valve.

第１の発明は、複数の切換弁の切り換え量に応じてポンプ吐出量を分流するロードセンシング制御回路に関し、少なくとも一つのコンペンセータバルブの上記一方の圧力室をタンクに接続するドレン通路を設けるとともに、このドレン通路に、上記一方の圧力室の圧力を制御する圧力制御手段を設けた点に特徴を有する。   A first invention relates to a load sensing control circuit for diverting a pump discharge amount in accordance with a switching amount of a plurality of switching valves, providing a drain passage for connecting the one pressure chamber of at least one compensator valve to a tank, This drain passage is characterized in that pressure control means for controlling the pressure of the one pressure chamber is provided.

第２の発明は、上記圧力制御手段は分流比変更バルブからなるとともに、上記分流比変更バルブは、絞り位置と閉位置とに切り換え可能にした点に特徴を有する。   The second invention is characterized in that the pressure control means is composed of a diversion ratio changing valve, and the diversion ratio changing valve is switchable between a throttle position and a closed position.

第３の発明は、上記分流比変更バルブは、絞り位置における開度を可変にした点に特徴を有する。   The third invention is characterized in that the diversion ratio changing valve has a variable opening at the throttle position.

第４の発明は、上記圧力制御手段が、上記切換弁及びコンペンセータバルブ間と上記分流比変更バルブとを接続する通路過程に設けた絞り手段とからなり、上記分流比変更バルブの絞り位置における絞り部と絞り手段との少なくとも一方を可変絞りにした点に特徴を有する。   According to a fourth aspect of the present invention, the pressure control means comprises throttle means provided in a passage process connecting the switching valve and the compensator valve and the diversion ratio change valve, and the restriction at the throttle position of the diversion ratio change valve It is characterized in that at least one of the section and the diaphragm means is a variable diaphragm.

第１の発明のロードセンシング制御回路によれば、少なくとも一つのコンペンセータバルブにおける一方の圧力室をタンクに導くドレン通路に圧力制御手段を設けたので、この圧力制御手段によって上記一方の圧力室の圧力を制御できる。 したがって、例えば、分流比を大きくしたいアクチュエータに対して、相対的に分流比を小さくしたいアクチュエータに接続したコンペンセータバルブにおける上記一方の圧力室の圧力を低く保つようにすれば、このコンペンセータバルブの開度を小さく保つことができる。   According to the load sensing control circuit of the first invention, the pressure control means is provided in the drain passage for guiding one pressure chamber of the at least one compensator valve to the tank, so that the pressure of the one pressure chamber is controlled by the pressure control means. Can be controlled. Therefore, for example, if the pressure of the one pressure chamber in the compensator valve connected to the actuator whose relative shunt ratio is relatively low with respect to the actuator whose relative shunt ratio is to be kept low, the opening of the compensator valve Can be kept small.

このように特定のコンペンセータバルブの開度を小さくできれば、それに接続したアクチュエータに対する供給流量を少なくできるので、相対的には目的とするアクチュエータへの供給流量を多くできる。
したがって、特殊なブームシリンダなどを組み込んだ建設機械等においても、その出荷段階において、当該ロードセンシング制御回路の圧力制御手段をチューニングするだけで対応できることになる。
また、作業状況に応じて特定のアクチュエータの分流比を変更する必要が発生した場合にも、その作業現場において圧力制御手段をチューニングするだけで対応することができる。 If the opening degree of a specific compensator valve can be reduced in this way, the supply flow rate to the actuator connected thereto can be reduced, so that the supply flow rate to the target actuator can be relatively increased.
Therefore, even a construction machine incorporating a special boom cylinder can be dealt with by simply tuning the pressure control means of the load sensing control circuit at the shipping stage.
In addition, even when it is necessary to change the diversion ratio of a specific actuator according to the work situation, it can be dealt with by simply tuning the pressure control means at the work site.

第２の発明のロードセンシング制御回路によれば、上記制御手段を絞り位置と閉位置とからなる分流比変更バルブで構成したので、この分流比変更バルブを閉位置に保つことによって、あらかじめ決められた設計上の仕様通りのコンペンセータバルブとして使用することができる。
また、上記分流比変更バルブを絞り位置に保つことによって、当該コンペンセータバルブを接続した切換弁の分流比を、相対的に小さくすることができる。 According to the load sensing control circuit of the second aspect of the invention, the control means is constituted by a diversion ratio changing valve composed of a throttle position and a closed position. Therefore, the control means can be determined in advance by keeping the diversion ratio changing valve in the closed position. It can be used as a compensator valve as designed.
Further, by maintaining the diversion ratio changing valve at the throttle position, the diversion ratio of the switching valve to which the compensator valve is connected can be made relatively small.

第３の発明のロードセンシング制御回路によれば、分流比変更バルブの絞り位置における絞り部の開度を可変にしたので、絞り部の可変制御が可能な範囲で、分流比を自由に設定できる。   According to the load sensing control circuit of the third aspect of the invention, since the opening degree of the throttle part at the throttle position of the shunt ratio changing valve is made variable, the shunt ratio can be freely set within a range in which variable control of the throttle part is possible. .

第４の発明のロードセンシング制御回路によれば、上記圧力制御手段を、上記分流比変更バルブと、絞り手段とで構成するとともに、分流比変更バルブの絞り位置における絞り部と絞り手段との少なくとも一方を可変絞りにしたので、分流比変更バルブと絞り手段とのいずれか一方をダンパーとして利用することができる。   According to the load sensing control circuit of the fourth invention, the pressure control means is composed of the diversion ratio change valve and the restriction means, and at least the restriction portion and the restriction means at the restriction position of the diversion ratio change valve. Since one of them is a variable throttle, either the diversion ratio changing valve or the throttle means can be used as a damper.

この発明の実施形態を示す回路図である。1 is a circuit diagram showing an embodiment of the present invention. 従来のロードセンシング制御回路を示す図である。It is a figure which shows the conventional load sensing control circuit.

図１に示した実施形態は、そのロードセンシング制御回路としての基本的な構成は従来と同様である。したがって、従来と同様の構成要素については同一の符号を付して説明するとともに、同一の構成要素については簡略化して説明する。   The basic configuration of the embodiment shown in FIG. 1 as a load sensing control circuit is the same as the conventional one. Therefore, the same constituent elements as those in the related art will be described with the same reference numerals, and the same constituent elements will be described in a simplified manner.

可変容量型ポンプ１には切換弁Ｖ１，Ｖ２を接続している。この切換弁Ｖ１，Ｖ２には、図示しないスプールが摺動自在に組み込まれている。なお、切換弁Ｖ１，Ｖ２は、スプールのストロークに応じてその開度を可変にするものなので、図１においても、切換弁Ｖ１，Ｖ２を可変オリフィスの記号で示している。
また、この発明における切換弁Ｖ１，Ｖ２は、そのスプールのストロークに応じて開度を可変にするものであれば、どのようなタイプの切換弁であってもよい。 The variable displacement pump 1 is connected to switching valves V1 and V2. A spool (not shown) is slidably incorporated in the switching valves V1 and V2. Note that the switching valves V1 and V2 are variable in opening according to the stroke of the spool, and therefore, the switching valves V1 and V2 are also indicated by symbols of variable orifices in FIG.
Further, the switching valves V1, V2 in the present invention may be any type of switching valve as long as the opening degree is variable according to the stroke of the spool.

上記のようにした切換弁Ｖ１，Ｖ２の下流には、コンペンセータバルブＣ１，Ｃ２を接続するとともに、このコンペンセータバルブＣ１，Ｃ２の下流にアクチュエータＡ１，Ａ２を接続している。そして、これら両アクチュエータＡ１，Ａ２のヘッド側室２，３のそれぞれは最高負荷圧を選択するシャトル弁からなる選択手段４に接続され、この選択手段４によって、上記ヘッド側室２，３のうちのどちらか高いほうの負荷圧Ｐ２が選択される。   The compensator valves C1 and C2 are connected downstream of the switching valves V1 and V2 as described above, and the actuators A1 and A2 are connected downstream of the compensator valves C1 and C2. Each of the head side chambers 2 and 3 of both actuators A1 and A2 is connected to a selection means 4 comprising a shuttle valve for selecting the maximum load pressure, and by this selection means 4, which of the head side chambers 2 and 3 is selected. The higher load pressure P2 is selected.

なお、上記選択手段４は必ずしもシャトル弁に限定されるものではなく、要するに最高負荷圧を選択できる機能さえ備えていれば、構造的に限定される必要はない。
また、この実施形態では、アクチュエータは２つしか示されていないが、アクチュエータが、システム的に当該ロードセンシング制御回路と一体になっていれば、アクチュエータの数は問わない。ただし、この場合に、各アクチュエータがコンペンセータバルブに対応付けられていることは必須である。 Note that the selection means 4 is not necessarily limited to a shuttle valve, and need not be structurally limited as long as it has a function of selecting the maximum load pressure.
In this embodiment, only two actuators are shown, but the number of actuators is not limited as long as the actuators are integrated with the load sensing control circuit systematically. However, in this case, it is essential that each actuator is associated with a compensator valve.

上記選択手段４で選択された最高負荷圧Ｐ２は、上記可変容量型ポンプ１に設けたレギュレータ５に導かれ、その最高負荷圧Ｐ２に応じて、可変容量型ポンプ１の傾転角が制御され、当該可変容量型ポンプ１が上記最高負荷圧Ｐ２に対応した吐出圧Ｐ１と吐出量を保つようにしている。
なお、図中符号Ｔはタンク、６はレギュレータ５とタンクＴとの間の圧力を保つためのオリフィスである。 The maximum load pressure P2 selected by the selection means 4 is guided to the regulator 5 provided in the variable displacement pump 1, and the tilt angle of the variable displacement pump 1 is controlled according to the maximum load pressure P2. The variable displacement pump 1 maintains the discharge pressure P1 and the discharge amount corresponding to the maximum load pressure P2.
In the figure, reference numeral T denotes a tank, and 6 denotes an orifice for maintaining the pressure between the regulator 5 and the tank T.

コンペンセータバルブＣ１，Ｃ２は、一方の圧力室９，１０と他方の圧力室１１，１２とを設け、これら一方の圧力室９，１０と他方の圧力室１１，１２との圧力作用で開度が制御される。
さらに詳しくは、コンペンセータバルブＣ１，Ｃ２には、図示しないスプール（以下「コンペスプール」という）を摺動自在に設けるとともに、このコンペスプールの一端を上記一方の圧力室９，１０に臨ませ、他端を上記他方の圧力室１１，１２に臨ませている。そして、このコンペスプールは、一方の圧力室９，１０と他方の圧力室１１，１２との圧力作用で、移動位置が制御されるとともに、その移動位置に応じて、切換弁Ｖ１，Ｖ２からアクチュエータＡ１，Ａ２にいたる過程の開度が制御される。 The compensator valves C1 and C2 are provided with one pressure chambers 9 and 10 and the other pressure chambers 11 and 12, and the opening degree is increased by the pressure action between the one pressure chambers 9 and 10 and the other pressure chambers 11 and 12. Be controlled.
More specifically, the compensator valves C1 and C2 are each provided with a spool (not shown) (hereinafter referred to as “compet spool”) slidably, and one end of the compensator spool faces the one pressure chamber 9, 10, and the other. The end faces the other pressure chamber 11, 12. The competition spool is controlled by the pressure action between the one pressure chamber 9 and 10 and the other pressure chamber 11 and 12, and the actuator is operated from the switching valves V1 and V2 according to the movement position. The opening degree in the process from A1 to A2 is controlled.

なお、上記コンペンセータバルブＣ１，Ｃ２は、そのコンペスプールの一端を一方の圧力室９，１０に臨ませ、他端を他方の圧力室１１，１２に臨ませるとともに、これら両圧力室９，１０と１１，１２とにおける圧力の作用力がバランスする位置において、当該コンペンセータバルブＣ１，Ｃ２の開度が保たれるものであれば、構造的に限定される必要はない。   The compensator valves C1 and C2 have one end of the competition spool facing the one pressure chambers 9 and 10 and the other end facing the other pressure chambers 11 and 12, As long as the opening degree of the compensator valves C1 and C2 is maintained at a position where the acting force of pressure in the pressure balances 11 and 12 is balanced, there is no need to be structurally limited.

また、上記一方の圧力室９，１０には、当該コンペンセータバルブＣ１，Ｃ２と切換弁Ｖ１，Ｖ２との間の圧力Ｐ３，Ｐ４が導かれ、他方の圧力室１１，１２には、選択手段４で選択された最高負荷圧Ｐ２が導かれる。ただし、上記圧力Ｐ３，Ｐ４は、切換弁Ｖ１，Ｖ２の開度に応じた圧力損失分だけ、可変容量型ポンプ１の吐出圧Ｐ１よりも低くなるのは当然である。   Further, pressures P3 and P4 between the compensator valves C1 and C2 and the switching valves V1 and V2 are guided to the one pressure chambers 9 and 10, and selection means 4 is provided to the other pressure chambers 11 and 12, respectively. The maximum load pressure P2 selected in (1) is derived. However, the pressures P3 and P4 are naturally lower than the discharge pressure P1 of the variable displacement pump 1 by a pressure loss corresponding to the opening degree of the switching valves V1 and V2.

さらに、上記圧力Ｐ３，Ｐ４は、アクチュエータＡ１，Ａ２の負荷圧に比例して変化する。例えば、アクチュエータＡ１，Ａ２の負荷圧が高くなれば、それにともなって圧力Ｐ３，Ｐ４も高くなるし、負荷圧が低くなれば圧力Ｐ３，Ｐ４も低くなる。
したがって、コンペンセータバルブＣ１，Ｃ２の一方の圧力室９，１０には、アクチュエータＡ１，Ａ２の負荷圧に応じて変化する圧力Ｐ３，Ｐ４が導かれることになる。 Further, the pressures P3 and P4 change in proportion to the load pressures of the actuators A1 and A2. For example, when the load pressure of the actuators A1 and A2 is increased, the pressures P3 and P4 are increased accordingly, and when the load pressure is decreased, the pressures P3 and P4 are also decreased.
Therefore, pressures P3 and P4 that change according to the load pressure of the actuators A1 and A2 are introduced into one of the pressure chambers 9 and 10 of the compensator valves C1 and C2.

そして、コンペンセータバルブＣ１，Ｃ２は、上記最高負荷圧Ｐ２と上記圧力Ｐ３，Ｐ４とがバランスする位置を保持するとともに、そのバランス位置において当該コンペンセータバルブＣ１，Ｃ２の開度を維持する。
例えば、他方の圧力室１１，１２に導かれる最高負荷圧Ｐ２に対して、反対側の一方の圧力室９，１０に導かれる圧力Ｐ３，Ｐ４の圧力が低ければ低いほどコンペンセータバルブＣ１，Ｃ２の開度が小さくなり、最高負荷圧Ｐ２と圧力Ｐ３，Ｐ４との相対差が小さくなればなるほど、コンペンセータバルブＣ１，Ｃ２の開度は大きくなる。 The compensator valves C1 and C2 maintain a position where the maximum load pressure P2 and the pressures P3 and P4 balance, and maintain the opening of the compensator valves C1 and C2 at the balance position.
For example, with respect to the maximum load pressure P2 guided to the other pressure chambers 11 and 12, the lower the pressures P3 and P4 guided to the one pressure chambers 9 and 10 on the opposite side, the lower the compensator valves C1 and C2. The smaller the opening and the smaller the relative difference between the maximum load pressure P2 and the pressures P3 and P4, the larger the opening of the compensator valves C1 and C2.

一方、両切換弁Ｖ１，Ｖ２が中立位置から切り換えられると、当該切換弁Ｖ１，Ｖ２は、その切り換え量に応じた開度を維持するが、これら両切換弁Ｖ１，Ｖ２の開度の比が、各アクチュエータＡ１，Ａ２に対する可変容量型ポンプ１の吐出量の分流比になる。   On the other hand, when the switching valves V1, V2 are switched from the neutral position, the switching valves V1, V2 maintain the opening according to the switching amount, but the ratio of the opening of the switching valves V1, V2 is Thus, the discharge ratio of the variable displacement pump 1 with respect to the actuators A1 and A2 is a diversion ratio.

しかし、切換弁Ｖ１，Ｖ２の開度で定めた分流比が一定だとしても、アクチュエータＡ１，Ａ２の負荷圧が変化してしまえば、切換弁Ｖ１，Ｖ２の開度によって定めた上記分流比が保たれなくなることは従来と同様である。また、アクチュエータＡ１，Ａ２の負荷圧が変化しても、コンペンセータバルブＣ１，Ｃ２が切換弁Ｖ１，Ｖ２の開度で定めた分流比を一定に保つ機能を果たす点も従来と同様である。   However, even if the diversion ratio determined by the opening degree of the switching valves V1, V2 is constant, if the load pressure of the actuators A1, A2 changes, the diversion ratio determined by the opening degree of the switching valves V1, V2 will be It is the same as before that it is not maintained. Moreover, even if the load pressure of the actuators A1 and A2 changes, the compensator valves C1 and C2 have the same function as the conventional one in that the function of keeping the diversion ratio determined by the opening degree of the switching valves V1 and V2 is maintained.

したがって、以下の説明において、一方のアクチュエータＡ１が最高負荷圧Ｐ２を維持し、他方のアクチュエータＡ２の負荷圧が上記最高負荷圧Ｐ２よりも低い場合であって、一度設定された切換弁Ｖ１，Ｖ２の開度は変化しないことを前提にする。   Therefore, in the following description, when one actuator A1 maintains the maximum load pressure P2, and the load pressure of the other actuator A2 is lower than the maximum load pressure P2, the switching valves V1, V2 set once are set. It is assumed that the opening degree of the valve does not change.

上記の場合に、可変容量型ポンプ１の吐出圧Ｐ１が最も高いのは当然である。そして、圧力Ｐ３は、コンペンセータバルブＣ１を流れる流体の圧力損失分だけ、アクチュエータＡ１の負荷圧すなわち最高負荷圧Ｐ２よりも高い圧力を維持する。したがって、各圧力は、Ｐ１＞Ｐ３＞Ｐ２の関係を保つ。   In the above case, it is natural that the discharge pressure P1 of the variable displacement pump 1 is the highest. The pressure P3 is maintained at a pressure higher than the load pressure of the actuator A1, that is, the maximum load pressure P2 by the pressure loss of the fluid flowing through the compensator valve C1. Therefore, each pressure maintains the relationship of P1> P3> P2.

上記の関係を維持している中で、一方のコンペンセータバルブＣ１のコンペスプールは、一方の圧力室９における圧力Ｐ３の作用力と他方の圧力室１１における最高負荷圧Ｐ２の作用力とがバランスする位置を保つとともに、コンペンセータバルブＣ１は、コンペスプールの上記位置における開度を維持する。   While maintaining the above relationship, the competing spool of one compensator valve C1 balances the acting force of the pressure P3 in one pressure chamber 9 and the acting force of the maximum load pressure P2 in the other pressure chamber 11. While maintaining the position, the compensator valve C1 maintains the opening of the competition spool at the above position.

そして、アクチュエータＡ１の負荷圧すなわち最高負荷圧Ｐ２が変化すれば、それに応じてコンペンセータバルブＣ１の開度も変化するとともに、その変化に応じて上記圧力Ｐ３も変化する。つまり、コンペンセータバルブＣ１の開度が大きくなれば、その分、このコンペンセータバルブＣ１を通過する流体の圧力損失が小さくなる。また、コンペンセータバルブＣ１の開度が小さくなれば、逆に、上記圧力損失が大きくなる。   When the load pressure of the actuator A1, that is, the maximum load pressure P2 changes, the opening of the compensator valve C1 changes accordingly, and the pressure P3 also changes according to the change. That is, if the opening degree of the compensator valve C1 increases, the pressure loss of the fluid passing through the compensator valve C1 decreases accordingly. On the contrary, if the opening of the compensator valve C1 is reduced, the pressure loss is increased.

また、アクチュエータＡ２側における圧力Ｐ４は、上記他方のコンペンセータバルブＣ２を通過する流体の圧力損失分だけ、当該アクチュエータＡ２の負荷圧よりも高い圧力を維持している。ただし、その圧力Ｐ４と上記最高負荷圧Ｐ２との相対差は上記アクチュエータＡ２の負荷圧に応じて異なることになる。
そして、他方のコンペンセータバルブＣ２は、一方の圧力室１０における圧力Ｐ４の作用力と他方の圧力室１２における最高負荷圧Ｐ２の作用力とがバランスする位置を保つとともに、コンペンセータバルブＣ２は、コンペスプールの上記位置における開度を維持する。 Further, the pressure P4 on the actuator A2 side maintains a pressure higher than the load pressure of the actuator A2 by the amount of pressure loss of the fluid passing through the other compensator valve C2. However, the relative difference between the pressure P4 and the maximum load pressure P2 varies depending on the load pressure of the actuator A2.
The other compensator valve C2 maintains a position where the acting force of the pressure P4 in one pressure chamber 10 and the acting force of the maximum load pressure P2 in the other pressure chamber 12 are balanced, and the compensator valve C2 The opening at the above position is maintained.

アクチュエータＡ２の負荷圧の変化に応じて圧力Ｐ４が変化すれば、それに応じてコンペンセータバルブＣ２の開度も変化する。コンペンセータバルブＣ２の開度が大きくなれば、その分、圧力損失が小さくなる。また、コンペンセータバルブＣ２の開度が小さくなれば、逆に圧力損失が大きくなる。   If the pressure P4 changes according to the change in the load pressure of the actuator A2, the opening degree of the compensator valve C2 also changes accordingly. As the opening of the compensator valve C2 increases, the pressure loss decreases accordingly. Moreover, if the opening degree of the compensator valve C2 is reduced, the pressure loss is increased.

今、一方のアクチュエータＡ１の最高負荷圧が一定で、他方のアクチュエータＡ２の負荷圧が、低くなる方向に変化したとすれば、それにともなって圧力Ｐ４も低くなる。しかし、このときには、コンペンセータバルブＣ２の開度が小さくなるので、そこを通過する流体の圧力損失が大きくなる。このように圧力損失が大きくなれば、アクチュエータＡ２の負荷圧が低くなったとしても、圧力Ｐ４は一定に保たれる。   Now, if the maximum load pressure of one actuator A1 is constant and the load pressure of the other actuator A2 changes in a decreasing direction, the pressure P4 also decreases accordingly. However, at this time, since the opening degree of the compensator valve C2 becomes small, the pressure loss of the fluid passing therethrough becomes large. If the pressure loss increases as described above, the pressure P4 is kept constant even if the load pressure of the actuator A2 is reduced.

したがって、アクチュエータＡ２の負荷圧の変化にかかわりなく、コンペンセータバルブＣ２の上流側の圧力Ｐ４が一定に保たれることになる。このようにアクチュエータＡ２の負荷圧の変化にかかわりなく圧力Ｐ４が一定に保たれるので、切換弁Ｖ２前後の差圧も一定に保たれる。切換弁Ｖ２前後の差圧が一定に保たれれば、アクチュエータＡ２の負荷圧の変化にかかわりなく、切換弁Ｖ２を通過する流量も一定に保たれる。言い換えると、切換弁Ｖ１，Ｖ２の開度で定められた分流比は、負荷圧の変化にかかわりなく一定に保たれることになる。   Accordingly, the pressure P4 on the upstream side of the compensator valve C2 is kept constant regardless of the change in the load pressure of the actuator A2. Thus, since the pressure P4 is kept constant regardless of the change in the load pressure of the actuator A2, the pressure difference across the switching valve V2 is also kept constant. If the differential pressure across the switching valve V2 is kept constant, the flow rate passing through the switching valve V2 is kept constant regardless of the change in the load pressure of the actuator A2. In other words, the diversion ratio determined by the opening degree of the switching valves V1 and V2 is kept constant regardless of the change in load pressure.

そして、この実施形態の最大の特徴は、アクチュエータＡ２側に設けたコンペンセータバルブＣ２の一方の圧力室１０を、タンクＴに接続するドレン通路１３を設け、このドレン通路１３に、上記一方の圧力室１０の圧力を制御する圧力制御手段である分流比変更バルブＣＶを設けた点である。
この分流比変更バルブＣＶは、分流比を小さくしたいアクチュエータ側に設けるものである。この実施形態では、一方のアクチュエータＡ１側の供給流量を相対的に多く確保するために、他方のアクチュエータＡ２側の分流比を小さくすることを想定し、他方のアクチュエータＡ２側のコンペンセータバルブＣ２に上記分流比変更バルブＣＶを接続している。 The greatest feature of this embodiment is that a drain passage 13 for connecting one pressure chamber 10 of the compensator valve C2 provided on the actuator A2 side to the tank T is provided, and the one pressure chamber is provided in the drain passage 13. This is the point that a diversion ratio changing valve CV, which is a pressure control means for controlling the pressure of 10, is provided.
This diversion ratio changing valve CV is provided on the actuator side where the diversion ratio is desired to be reduced. In this embodiment, in order to ensure a relatively large supply flow rate on the one actuator A1 side, it is assumed that the diversion ratio on the other actuator A2 side is reduced, and the compensator valve C2 on the other actuator A2 side is connected to the compensator valve C2. A diversion ratio changing valve CV is connected.

上記分流比変更バルブＣＶは、そのスプールの一端にスプリング１４のばね力を作用させるとともに、このスプリング１４とは反対側にパイロット室１５を設けている。
このようにした分流比変更バルブＣＶは、絞り位置と閉位置とに切り換え可能であり、通常は、スプリング１４のばね力の作用で図示のノーマル位置である閉位置を保持する。そして、パイロット室１５の圧力作用が上記スプリング１４のばね力に打ち勝つと、図面左側位置である絞り位置に切り換わる。 The diversion ratio changing valve CV applies a spring force of a spring 14 to one end of the spool, and a pilot chamber 15 is provided on the opposite side of the spring 14.
The diversion ratio changing valve CV thus configured can be switched between a throttle position and a closed position, and normally maintains the closed position, which is the normal position shown in the figure, by the action of the spring force of the spring 14. Then, when the pressure action of the pilot chamber 15 overcomes the spring force of the spring 14, the throttle position is switched to the left position in the drawing.

分流比変更バルブＣＶが上記閉位置にあるときには、コンペンセータバルブＣ２の一方の圧力室１０とタンクＴとの連通が遮断されるので、コンペンセータバルブＣ２は従来と同様に動作する。
しかし、分流比変更バルブＣＶが上記絞り位置に切り換わると、コンペンセータバルブＣ２の一方の圧力室１０が、絞りを介してタンクＴに連通する。したがって、このときの一方の圧力室１０の圧力は、分流比変更バルブＣＶが閉位置にあるときよりも低く設定される。 When the diversion ratio change valve CV is in the closed position, the communication between the one pressure chamber 10 of the compensator valve C2 and the tank T is cut off, so that the compensator valve C2 operates in the same manner as before.
However, when the diversion ratio changing valve CV is switched to the throttle position, one pressure chamber 10 of the compensator valve C2 communicates with the tank T via the throttle. Accordingly, the pressure in one pressure chamber 10 at this time is set lower than when the flow dividing ratio changing valve CV is in the closed position.

そのために、一方の圧力室１０の圧力と最高負荷圧Ｐ２との相対差が大きくなり、コンペンセータバルブＣ２は最小開度を維持することになる。
コンペンセータバルブＣ２が最小開度に維持されれば、アクチュエータＡ２側に供給される流量が少なくなるので、その少なくなった分だけ、一方のアクチュエータＡ１への供給流量が相対的に多く確保されることになる。 For this reason, the relative difference between the pressure in one pressure chamber 10 and the maximum load pressure P2 increases, and the compensator valve C2 maintains the minimum opening.
If the compensator valve C2 is maintained at the minimum opening, the flow rate supplied to the actuator A2 side is reduced. Therefore, a relatively high supply flow rate to one actuator A1 is ensured by the reduced amount. become.

上記のようにした分流比変更バルブＣＶは、パイロット室１５に導入されるパイロット圧を制御することによって、上記絞り位置における絞り部の開度を可変にすることができる。絞り部の開度を可変にするために、分流比変更バルブＣＶの切り換えに応じてその開度を段階的に変化させてもよいし、無段階的に変化させてもよい。
いずれにしても、上記絞り部の開度を自由に調整できれば、相対的に多くの供給流量を確保したいアクチュエータ側の状況に応じてコンペンセータバルブＣ２の一方の圧力室１０の圧力を自由に設定できる。 The diversion ratio changing valve CV configured as described above can vary the opening of the throttle portion at the throttle position by controlling the pilot pressure introduced into the pilot chamber 15. In order to make the opening degree of the throttle part variable, the opening degree may be changed stepwise according to switching of the flow dividing ratio changing valve CV, or may be changed steplessly.
In any case, if the opening of the throttle part can be freely adjusted, the pressure in one pressure chamber 10 of the compensator valve C2 can be freely set according to the situation on the actuator side where it is desired to ensure a relatively large supply flow rate. .

なお、上記分流比変更バルブＣＶは、それを手動で切り換えるようにしてもよいし、例えば、多くの流量を確保したい特定のアクチュエータを動作させるときのパイロット圧を、上記パイロット室１５に導くようにしてもよい。
また、分流比変更バルブＣＶは、複数のアクチュエータに対応させて設けてもよいし、すべてのアクチュエータに対応させて設けてもよい。ただし、少なくとも分流比を小さくしたいアクチュエータ側に設ければよい。 The diversion ratio changing valve CV may be switched manually. For example, a pilot pressure when operating a specific actuator for which a large flow rate is to be secured is guided to the pilot chamber 15. May be.
The diversion ratio changing valve CV may be provided corresponding to a plurality of actuators or may be provided corresponding to all actuators. However, it may be provided at least on the actuator side where the diversion ratio is desired to be reduced.

さらに、上記切換弁Ｖ２及びコンペンセータバルブＣ２の間と、上記分流比変更バルブＣＶとを接続する通路過程には、この発明の絞り手段を構成するオリフィス１６を設けているが、このオリフィス１６は開度を固定的に定めたものである。
このオリフィス１６は、コンペンセータバルブＣ２に対してダンパーオリフィスとして機能するものである。 Furthermore, an orifice 16 constituting the throttle means of the present invention is provided in the passage process connecting the switching valve V2 and the compensator valve C2 and the diversion ratio changing valve CV. The orifice 16 is opened. The degree is fixedly determined.
The orifice 16 functions as a damper orifice with respect to the compensator valve C2.

ただし、上記オリフィス１６を可変オリフィスにする一方、分流比変更バルブＣＶの絞り部を固定絞りにしてもよいし、それら両者を可変絞りにしてもよい。
そして、この発明の目的を達成するためには、上記絞り部あるいはオリフィスの少なくともいずれか一方は、可変にしておかなければならない。 However, while the orifice 16 is a variable orifice, the throttle portion of the flow dividing ratio changing valve CV may be a fixed throttle, or both of them may be a variable throttle.
In order to achieve the object of the present invention, at least one of the throttle portion and the orifice must be variable.

パワーショベル等の建設機械に最適である。   Ideal for construction machines such as power shovels.

１ 可変容量型ポンプ
Ｖ１，Ｖ２ 切換弁
Ａ１，Ａ２ アクチュエータ
Ｃ１，Ｃ２ コンペンセータバルブ
９〜１２ 圧力室
１３ ドレン通路
ＣＶ 分流比変更バルブ
１６ オリフィス 1 Variable displacement pumps V1, V2 Switching valves A1, A2 Actuators C1, C2 Compensator valves 9-12 Pressure chamber 13 Drain passage CV Split ratio changing valve 16 Orifice

Claims (4)

複数のアクチュエータと、
これらアクチュエータに圧力流体を供給する可変容量型ポンプと、
上記可変容量型ポンプ及び上記アクチュエータを接続する接続過程にそれぞれ設けた切換弁と、
この切換弁及び上記アクチュエータを接続する接続過程にそれぞれ設け、一方の圧力室と他方の圧力室とを有するコンペンセータバルブと、
複数の上記アクチュエータにおける最高負荷圧を選択する選択手段と
を備え、
上記コンペンセータバルブの一方の圧力室には、当該コンペンセータバブルが接続されたアクチュエータの負荷圧を導き、上記選択手段で選択された最高負荷圧をコンペンセータバルブの他方の圧力室に導き、これら両圧力室の圧力作用で当該コンペンセータバルブの開度を制御して、複数の切換弁の切り換え量に応じてポンプ吐出量を分流するロードセンシング制御回路において、
少なくとも一つの上記コンペンセータバルブの上記一方の圧力室をタンクに接続するドレン通路を設けるとともに、このドレン通路に、上記一方の圧力室の圧力を制御する圧力制御手段を設けてなるロードセンシング制御回路。 Multiple actuators;
A variable displacement pump that supplies pressure fluid to these actuators;
A switching valve provided in each connection process for connecting the variable displacement pump and the actuator;
A compensator valve having one pressure chamber and the other pressure chamber, respectively, provided in a connection process for connecting the switching valve and the actuator;
Selecting means for selecting the maximum load pressure in the plurality of actuators,
In one pressure chamber of the compensator valve, the load pressure of the actuator to which the compensator bubble is connected is led, and the highest load pressure selected by the selection means is led to the other pressure chamber of the compensator valve. In the load sensing control circuit for controlling the opening of the compensator valve by the pressure action of and diverting the pump discharge amount according to the switching amount of the plurality of switching valves,
A load sensing control circuit comprising a drain passage for connecting the one pressure chamber of at least one of the compensator valves to a tank, and a pressure control means for controlling the pressure of the one pressure chamber in the drain passage. 上記圧力制御手段は分流比変更バルブからなるとともに、上記分流比変更バルブは、絞り位置と閉位置とに切り換え可能にした請求項１に記載されたロードセンシング制御回路。   2. The load sensing control circuit according to claim 1, wherein the pressure control means comprises a diversion ratio changing valve, and the diversion ratio changing valve is switchable between a throttle position and a closed position. 上記分流比変更バルブは、絞り位置における絞り部の開度を可変にした請求項２に記載されたロードセンシング制御回路。   The load sensing control circuit according to claim 2, wherein the diversion ratio changing valve is configured such that an opening degree of a throttle portion at a throttle position is variable. 上記圧力制御手段は、上記切換弁及びコンペンセータバルブ間と上記分流比変更バルブとを接続する通路過程に設けた絞り手段とからなり、上記分流比変更バルブの絞り位置における絞り部と絞り手段との少なくとも一方を可変絞りにした請求項２に記載されたロードセンシング制御回路。

The pressure control means includes a throttle means provided in a passage process connecting the switching valve and the compensator valve and the diversion ratio change valve, and is provided between the throttle portion and the throttle means at the throttle position of the diversion ratio change valve. The load sensing control circuit according to claim 2, wherein at least one of them is a variable aperture.

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US14/898,161 US10024342B2 (en) 2014-05-26 2015-04-13 Load sensing control circuit
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DE112015000092.5T DE112015000092T5 (en) 2014-05-26 2015-04-13 Load measuring control circuit
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